Among the most ubiquitous effects of addictive drugs, but the least well studied, is drug craving. There has not even existed a validated psychometric instrument for the evaluation of craving that would lend itself to the systematic development of medications for treating drug craving. We are currently developing such instrumentation for cocaine, heroin, alcohol, and marijuana. This research should help us to identify mechanisms of addiction that are common across drug classes and therefore lead to a better understanding of the mechanisms that underlie the drug cravings. Our initial findings indicated that cocaine craving is a multidimensional construct, involving an admixture of urges and desire, intent to use, loss of control over use, and anticipation of positive outcome. A similar multidimensional structure was found among responses from subjects evaluated using the heroin instrument. One hundred sixty subjects have completed the new Alcohol Craving Questionnaire. The project has been modified to include measurement of craving and psychomotor or cognitive testing to examine the relationship between drug cravings and human performance. The Marijuana Craving Questionnaire has recently been completed and subject testing begun. The utility of computer administration of the series will be assessed to improve the efficiency of testing. Finally, to extend the generality of the research and investigate ethnic and cultural factors, a Standard Spanish version of the Cocaine Craving Questionnaires and Manual has also been developed. These advances in instrument development and enhanced understanding of craving should enable more rapid progress in the ability to produce more selective and effective medications and other interventions to meet the needs of those addicted to drugs. With these instruments we should be able to predict which craving dimensions may be relieved by medications and which will require other intervention to enable the person to achieve and sustain drug abstinence.